Remove frozen requirements

requirements-frozen.txt

-apistar==0.7.2
-certifi==2019.3.9
-chardet==3.0.4
-Click==7.0
-idna==2.8
-Jinja2==2.10
-MarkupSafe==1.1.1
-PyYAML==5.1
-requests==2.21.0
-six==1.15.0
-typesystem==0.2.2
-urllib3==1.24.1

setup.py

@@ -15,7 +15,7 @@ setup(
         exclude=["*.tests", "*.tests.*", "tests.*", "tests"],
     ),
     package_data={"": ["*.rst", "LICENSE", "README"], "arkindex": ["schema.yml"]},
-    install_requires=read_requirements("requirements-frozen.txt"),
+    install_requires=read_requirements("requirements.txt"),
     python_requires=">=3.6",
     license="MIT",
     description="API client for the Arkindex project",